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Sticker of Knapweed root weevil
Bug card No. 2458 of 4,939

Knapweed root weevil

Cyphocleonus achates
Eats: PlantsBeetlesGardens and meadows6 legs

The knapweed root weevil is a dark grey beetle speckled with white, with a long snout like all weevils. It is a helper for farmers. People brought it to North America to fight knapweeds, weedy plants that take over fields.

Lives in
Southern Europe and around the Mediterranean, now also in North America and India
Length
1.4 to 1.5 cm (0.55 to 0.59 in)
Top speed
about 0.16 km/h (0.1 mph)
On foot, estimate
Can it hurt you?
Harmless
Harmless to people. It only damages knapweed plants.
What does it eat?
The grown-up weevil eats knapweed leaves. Its larva tunnels into the knapweed root and eats it from the inside.
For real!Photo of Knapweed root weevil
Picture by Kenny Chabba. CC BY-SA 4.0, via Wikimedia Commons.

How big is it?

How long is it?

Knapweed root weevil about 1.5 cm long (0.59 in)A grain of rice about 6 mm (0.24 in)A toy building brick about 3.2 cm (1.3 in)A crayon about 9 cm (3.5 in)
as long as 2.5 grains of rice in a rowcould run across a dinner table in 22 seconds

How big is Knapweed root weevil compared to YOU?

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How fast is it?

cool stuff

Fun facts

1

The mother digs little notches into the top of the knapweed root and lays one egg in each.

2

A female lays about 100 eggs during her life as a grown-up weevil, which lasts 8 to 15 weeks.

3

Its larva can kill a small knapweed plant by eating the inside of its root.

4

It was first set free in the United States in the 1980s to fight weedy knapweeds.

5

Scientists checked that it does not attack the native plants of North America.

you asked

Most asked questions about Knapweed root weevil

?What does the knapweed root weevil eat?

Knapweed. The grown-ups eat the leaves and the larvae eat the roots.

?How big is the knapweed root weevil?

It is about 14 to 15 millimetres long.

?Why did people bring it to North America?

To fight knapweeds, weeds that spread over fields. It eats them without harming native plants.

For bug experts

Scientific name
Cyphocleonus achates
Group
Beetles
Family
Curculionidae
Classification
Insecta > Coleoptera > Curculionidae
Lives on
Europe, North America, Asia

Where the facts come from

  1. Cyphocleonus achates (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
  2. Picture by Kenny Chabba. CC BY-SA 4.0, Wikimedia Commons. The sticker of this bug is drawn from this picture.

If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at [email protected] and we will fix it.

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